In brief. If the environment temperature is raised, a point is reached whereby, heat loss mechanisms cannot be activated any further. This is called the high critical temperature. It varies considerably depending on the level of humidity and air movements. For example in hot, dry and windy conditions, the high critical temperature is far above that of the normal body temperature. This is because under those conditions, sweat evaporates rapidly thus cooling the body. On the other hand, in humid conditions, the high critical temperature is only around the normal body temperature. This is because under those conditions sweat only evaporates very slowly.
Once the high critical temperature is reached, the body temperature starts to rise and the metabolic rate starts to go up. They continue doing so as long as the environmental temperature rises. The increased metabolic rate results in further heat production, causing a further heat production, causing a further increase in body temperature : a very good example of positive feedback. Eventually, the animal goes into a state of hyperthermia-high body temperature-followed by death at the upper lethal temperature, which in man is 42 degrees centigrade.
One of water properties is : Water has a high heat capacity. This means that absorption of a large amount of heat energy results in only a relatively small rise in temperature. In view of this water property, for the first time ever, FIFA mandated compulsory three-minute hydration breaks in every single at the 2026 tournament for players to replenish water loss through evaporation. And cooling effect from water absorbing heat from body hence averting death on the pitch. This is my considered opinion.